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pa.c (pa_adjust_insn_length): Rewrite so that it only adjusts insns which really need adjustment. 

* pa.c (pa_adjust_insn_length): Rewrite so that it only adjusts
        insns which really need adjustment.
        (output_cbranch): Rework so that output templates are simpler.
        Use shorter sequence for long backwards conditional branches with
        a filled delay slot that is nullified.  More agressively use "skip"
        instructions.  More agressively nullify the delay slot if nothing
        useful could be placed there.
        (output_bb): Likewise.
	(forward_branch_p): New function.

From-SVN: r4875
This commit is contained in:
Jeff Law 1993-07-07 14:40:06 -06:00
parent f65590a907
commit b9821af87b
1 changed files with 153 additions and 84 deletions
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237
gcc/config/pa/pa.c
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@ -2492,17 +2492,12 @@ pa_adjust_cost (insn, link, dep_insn, cost)
/* Return any length adjustment needed by INSN which already has its length
computed as LENGTH. Return zero if no adjustment is necessary.
For the PA: function calls, millicode calls, and short conditional branches
with unfilled delay slots need an adjustment by +1 (to account for
the NOP which will be inserted into the instruction stream).
For the PA: function calls, millicode calls, and backwards short
conditional branches with unfilled delay slots need an adjustment by +1
(to account for the NOP which will be inserted into the instruction stream).
Also compute the length of an inline block move here as it is too
complicated to express as a length attribute in pa.md.
(For 2.5) Indirect calls do not need length adjustment as their
delay slot is filled internally in the output template.
(For 2.5) No adjustment is necessary for jump tables or casesi insns. */
complicated to express as a length attribute in pa.md. */
int
pa_adjust_insn_length (insn, length)
rtx insn;
@ -2510,9 +2505,20 @@ pa_adjust_insn_length (insn, length)
{
rtx pat = PATTERN (insn);
/* Call insn with an unfilled delay slot. */
/* Call insns which are *not* indirect and have unfilled delay slots. */
if (GET_CODE (insn) == CALL_INSN)
return 1;
{
if (GET_CODE (XVECEXP (pat, 0, 0)) == CALL
&& GET_CODE (XEXP (XEXP (XVECEXP (pat, 0, 0), 0), 0)) == SYMBOL_REF)
return 1;
else if (GET_CODE (XVECEXP (pat, 0, 0)) == SET
&& GET_CODE (XEXP (XEXP (XEXP (XVECEXP (pat, 0, 0), 1), 0), 0))
== SYMBOL_REF)
return 1;
else
return 0;
}
/* Millicode insn with an unfilled delay slot. */
else if (GET_CODE (insn) == INSN
&& GET_CODE (pat) != SEQUENCE
@ -2529,9 +2535,24 @@ pa_adjust_insn_length (insn, length)
&& GET_MODE (XEXP (XVECEXP (pat, 0, 0), 1)) == BLKmode)
return compute_movstrsi_length (insn) - 1;
/* Conditional branch with an unfilled delay slot. */
else if (GET_CODE (insn) == JUMP_INSN && ! simplejump_p (insn)
&& length != 2 && length != 4)
return 1;
else if (GET_CODE (insn) == JUMP_INSN && ! simplejump_p (insn))
{
/* Adjust a short backwards conditional with an unfilled delay slot. */
if (GET_CODE (pat) == SET
&& length == 1
&& ! forward_branch_p (insn))
return 1;
/* Adjust dbra insn with short backwards conditional branch with
unfilled delay slot -- only for case where counter is in a register. */
else if (GET_CODE (pat) == PARALLEL
&& GET_CODE (XVECEXP (pat, 0, 1)) == SET
&& GET_CODE (XEXP (XVECEXP (pat, 0, 1), 0)) == REG
&& length == 1
&& ! forward_branch_p (insn))
return 1;
else
return 0;
}
else
return 0;
}
@ -3233,19 +3254,30 @@ output_cbranch (operands, nullify, length, negated, insn)
static char buf[100];
int useskip = 0;
/* If this is a long branch with its delay slot unfilled, set `nullify'
as it can nullify the delay slot and save a nop. */
if (length == 2 && dbr_sequence_length () == 0)
nullify = 1;
/* If this is a short forward conditional branch which did not get
its delay slot filled, the delay slot can still be nullified. */
if (! nullify && length == 1 && dbr_sequence_length () == 0)
nullify = forward_branch_p (insn);
/* A forward branch over a single nullified insn can be done with a
comclr instruction. This avoids a single cycle penalty due to
mis-predicted branch if we fall through (branch not taken). */
if (length == 1
&& JUMP_LABEL (insn) == next_nonnote_insn (NEXT_INSN (insn))
&& next_real_insn (insn) != 0
&& get_attr_length (next_real_insn (insn)) == 1
&& JUMP_LABEL (insn) == next_nonnote_insn (next_real_insn (insn))
&& nullify)
useskip = 1;
switch (length)
{
/* Short conditional branch. May nullify either direction. */
/* All short conditional branches except backwards with an unfilled
delay slot. */
case 1:
if (useskip)
strcpy (buf, "com%I2clr,");
@ -3260,41 +3292,43 @@ output_cbranch (operands, nullify, length, negated, insn)
else if (nullify)
strcat (buf, ",n %2,%1,%0");
else
strcat (buf, " %2,%1,%0%#");
strcat (buf, " %2,%1,%0");
break;
/* Long conditional branch, possible forward nullification. Also
note all conditional branches have a length of 4 when not
optimizing! */
/* All long conditionals. Note an short backward branch with an
unfilled delay slot is treated just like a long backward branch
with an unfilled delay slot. */
case 2:
case 4:
strcpy (buf, "com%I2clr,");
if (negated)
strcat (buf, "%S3");
/* Handle weird backwards branch with a filled delay slot
with is nullified. */
if (dbr_sequence_length () != 0
&& ! forward_branch_p (insn)
&& nullify)
{
strcpy (buf, "com%I2b,");
if (negated)
strcat (buf, "%S3");
else
strcat (buf, "%B3");
strcat (buf, ",n %2,%1,.+12\n\tbl %0,0");
}
else
strcat (buf, "%B3");
/* Nullify the delay slot if the delay slot was explicitly
nullified by the delay branch scheduler or if no insn
could be placed in the delay slot. */
if (nullify)
strcat (buf, " %2,%1,0\n\tbl,n %0,0");
else
strcat (buf, " %2,%1,0\n\tbl%* %0,0");
break;
/* Long backward conditional branch with nullification. */
case 3:
strcpy (buf, "com%I2b,");
if (negated)
strcat (buf, "%S3");
else
strcat (buf, "%B3");
strcat (buf, " %2,%1,.+16\n\tnop\n\t bl %0,0");
{
strcpy (buf, "com%I2clr,");
if (negated)
strcat (buf, "%S3");
else
strcat (buf, "%B3");
if (nullify)
strcat (buf, " %2,%1,0\n\tbl,n %0,0");
else
strcat (buf, " %2,%1,0\n\tbl %0,0");
}
break;
default:
abort();
}
}
return buf;
}
@ -3313,19 +3347,32 @@ output_bb (operands, nullify, length, negated, insn, which)
static char buf[100];
int useskip = 0;
/* If this is a long branch with its delay slot unfilled, set `nullify'
as it can nullify the delay slot and save a nop. */
if (length == 2 && dbr_sequence_length () == 0)
nullify = 1;
/* If this is a short forward conditional branch which did not get
its delay slot filled, the delay slot can still be nullified. */
if (! nullify && length == 1 && dbr_sequence_length () == 0)
nullify = forward_branch_p (insn);
/* A forward branch over a single nullified insn can be done with a
extrs instruction. This avoids a single cycle penalty due to
mis-predicted branch if we fall through (branch not taken). */
if (length == 1
&& JUMP_LABEL (insn) == next_nonnote_insn (NEXT_INSN (insn))
&& next_real_insn (insn) != 0
&& get_attr_length (next_real_insn (insn)) == 1
&& JUMP_LABEL (insn) == next_nonnote_insn (next_real_insn (insn))
&& nullify)
useskip = 1;
switch (length)
{
/* Short conditional branch. May nullify either direction. */
/* All short conditional branches except backwards with an unfilled
delay slot. */
case 1:
if (useskip)
strcpy (buf, "extrs,");
@ -3343,52 +3390,54 @@ output_bb (operands, nullify, length, negated, insn, which)
else if (nullify && ! negated)
strcat (buf, ",n %0,%1,%2");
else if (! nullify && negated)
strcat (buf, "%0,%1,%3%#");
strcat (buf, "%0,%1,%3");
else if (! nullify && ! negated)
strcat (buf, " %0,%1,%2%#");
strcat (buf, " %0,%1,%2");
break;
/* Long conditional branch, possible forward nullification. Also
note all conditional branches have a length of 4 when not
optimizing! */
/* All long conditionals. Note an short backward branch with an
unfilled delay slot is treated just like a long backward branch
with an unfilled delay slot. */
case 2:
case 4:
strcpy (buf, "extrs,");
if ((which == 0 && negated)
|| (which == 1 && ! negated))
strcat (buf, "<");
/* Handle weird backwards branch with a filled delay slot
with is nullified. */
if (dbr_sequence_length () != 0
&& ! forward_branch_p (insn)
&& nullify)
{
strcpy (buf, "bb,");
if ((which == 0 && negated)
|| (which == 1 && ! negated))
strcat (buf, "<");
else
strcat (buf, ">=");
if (negated)
strcat (buf, " %0,%1,.+12\n\tbl %3,0");
else
strcat (buf, " %0,%1,.+12\n\tbl %2,0");
}
else
strcat (buf, ">=");
/* Nullify the delay slot if the delay slot was explicitly
nullified by the delay branch scheduler or if no insn
could be placed in the delay slot. */
if (nullify && negated)
strcat (buf, " %0,%1,1,0\n\tbl,n %3,0");
else if (nullify && ! negated)
strcat (buf, " %0,%1,1,0\n\tbl,n %2,0");
else if (negated)
strcat (buf, " %0,%1,1,0\n\tbl%* %3,0");
else
strcat (buf, " %0,%1,1,0\n\tbl%* %2,0");
break;
/* Long backward conditional branch with nullification. */
case 3:
strcpy (buf, "bb,");
if ((which == 0 && negated)
|| (which == 1 && ! negated))
strcat (buf, "<");
else
strcat (buf, ">=");
if (negated)
strcat (buf, " %0,%1,.+16\n\tnop\n\t bl %3,0");
else
strcat (buf, " %0,%1,.+16\n\tnop\n\t bl %2,0");
{
strcpy (buf, "extrs,");
if ((which == 0 && negated)
|| (which == 1 && ! negated))
strcat (buf, "<");
else
strcat (buf, ">=");
if (nullify && negated)
strcat (buf, " %0,%1,1,0\n\tbl,n %3,0");
else if (nullify && ! negated)
strcat (buf, " %0,%1,1,0\n\tbl,n %2,0");
else if (negated)
strcat (buf, " %0,%1,1,0\n\tbl %3,0");
else
strcat (buf, " %0,%1,1,0\n\tbl %2,0");
}
break;
default:
abort();
}
}
return buf;
}
@ -3534,3 +3583,23 @@ shadd_operand (op, mode)
{
return (GET_CODE (op) == CONST_INT && shadd_constant_p (INTVAL (op)));
}
/* Return 1 if INSN branches forward. Should be using insn_addresses
to avoid walking through all the insns... */
int
forward_branch_p (insn)
rtx insn;
{
rtx label = JUMP_LABEL (insn);
while (insn)
{
if (insn == label)
break;
else
insn = NEXT_INSN (insn);
}
return (insn == label);
}